The translation of visual cell m-RNA will be studied in both the cell-free, reticulocyte lysate system and in isolated, cultured oocytes of Xenopus laevis. The visual cell m-RNA will be contained in extracts of the whole retina. Cattle, rat, ground squirrel and chicken retinas will be used in order to compare predominantly rod with predominantly cone retinas. Solubilized RNA will be fractionated by affinity chromatography with oligo-d(thymidine) cellulose to obtain poly-(A) m-RNA. The marker for visual cell m-RNA will be opsin m-RNA identified by its product. Opsin identification will be done by immunoprecipitation and two-dimensional gel electrophoresis. Quantitative data of the efficiency of opsin translation in-vitro will be attempted in order to assess (a) the stability of visual m-RNA and (b) the state of mRNA synthesis in the rat under different conditions of normal and abnormal visual cell function. The m-RNA will be microinjected into oocytes cultured in the presence of 11-cis retinal. The injected oocyte will be tested by intracellular current and voltage electrodes for responsiveness to light in conjunction with thorough testing of its electrophysiological properties in comparison with appropriate controls. Extracts will be analyzed for opsin translation after oocyte incubation in 3H-leucine. Finally, the localization of translated opsin will be examined by membrane fractionation and immunocytochemical techniques in cooperation with Dr. Papermaster, Yale University.